On 2020/3/10 04:21, Gustavo A. R. Silva wrote:> The current codebase makes use of the zero-length array language> extension to the C90 standard, but the preferred mechanism to declare> variable-length types such as these ones is a flexible array member[1][2],> introduced in C99:> > struct foo {> int stuff;> struct boo array[];> };> > By making use of the mechanism above, we will get a compiler warning> in case the flexible array does not occur last in the structure, which> will help us prevent some kind of undefined behavior bugs from being> inadvertently introduced[3] to the codebase from now on.> > Also, notice that, dynamic memory allocations won't be affected by> this change:> > "Flexible array members have incomplete type, and so the sizeof operator> may not be applied. As a quirk of the original implementation of> zero-length arrays, sizeof evaluates to zero."[1]> > This issue was found with the help of Coccinelle.> > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html> [2] https://github.com/KSPP/linux/issues/21> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")> > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>